diff --git a/src/Box2D.NET/B2Joints.cs b/src/Box2D.NET/B2Joints.cs
index 28fe25e..30b9e07 100644
--- a/src/Box2D.NET/B2Joints.cs
+++ b/src/Box2D.NET/B2Joints.cs
@@ -75,6 +75,8 @@ public static b2FilterJointDef b2DefaultFilterJointDef()
             return def;
         }
 
+        /// Use this to initialize your joint definition
+        /// @ingroup prismatic_joint
         public static B2PrismaticJointDef b2DefaultPrismaticJointDef()
         {
             B2PrismaticJointDef def = new B2PrismaticJointDef();